use polyglot for detecting the language

app/app.py

@@ -6,6 +6,7 @@ from langdetect import detect_langs
 from langdetect import DetectorFactory
 from pkg_resources import resource_filename
 from .api_keys import Database
+from app.language import detect_languages
 
 DetectorFactory.seed = 0 # deterministic
 
@@ -57,11 +58,6 @@ def create_app(args):
     from app.language import languages
     app = Flask(__name__)
 
-    # For faster access
-    language_map = {}
-    for l in languages:
-        language_map[l.code] = l.name
-
     if args.debug:
         app.config['TEMPLATES_AUTO_RELOAD'] = True
 
@@ -271,19 +267,12 @@ def create_app(args):
               abort(400, description="Invalid request: Request (%d) exceeds character limit (%d)" % (chars, args.char_limit))
 
         if source_lang == 'auto':
-            candidate_langs = list(filter(lambda l: l.lang in language_map, detect_langs(q)))
-
-            if len(candidate_langs) > 0:
-                candidate_langs.sort(key=lambda l: l.prob, reverse=True)
+            candidate_langs = detect_languages(q)
 
             if args.debug:
                 print(candidate_langs)
 
-                source_lang = next(iter([l.code for l in languages if l.code == candidate_langs[0].lang]), None)
-                if not source_lang:
-                    source_lang = 'en'
-            else:
-                source_lang = 'en'
+            source_lang = candidate_langs[0]["language"]
 
             if args.debug:
                 print("Auto detected: %s" % source_lang)
@@ -385,12 +374,7 @@ def create_app(args):
         if not q:
             abort(400, description="Invalid request: missing q parameter")
 
-        candidate_langs = list(filter(lambda l: l.lang in language_map, detect_langs(q)))
-        candidate_langs.sort(key=lambda l: l.prob, reverse=True)
-        return jsonify([{
-            'confidence': l.prob,
-            'language': l.lang
-        } for l in candidate_langs])
+        return jsonify(detect_languages(q))
 
 
     @app.route("/frontend/settings")

app/language.py

@@ -1,3 +1,36 @@
 from argostranslate import translate
+from polyglot.detect.base import Detector
+
 
 languages = translate.load_installed_languages()
+
+
+__lang_codes = [l.code for l in languages]
+
+
+def detect_languages(text):
+    f = Detector(text).languages
+
+    # get the candidates
+    candidate_langs = list(filter(lambda l: l.read_bytes != 0 and l.code in __lang_codes, f))
+
+    # this happens if no language can be detected
+    if not candidate_langs:
+        # use language "en" by default but with zero confidence
+        return [
+                    {
+                        'confidence': 0.0,
+                        'language': "en"
+                    }
+                ]
+
+    # sort the candidates descending based on the detected confidence
+    candidate_langs.sort(key=lambda l: l.confidence, reverse=True)
+
+    return [
+                {
+                    'confidence': l.confidence,
+                    'language': l.code
+                }
+                for l in candidate_langs
+            ]